Engineering and Computer Science Faculty Publications

CedarLogic - A New Graphical Digital Logic CAD Tool to Aid in the Teaching of Digital Logic Design

Document Type

Conference Proceeding

Publication Date


Journal Title

Proceedings of the 2007 ASEE Annual Conference and Symposium

First Page


Last Page



This paper describes "CedarLogic" a graphical digital logic simulator that three senior undergraduate students created in fulfillment of their Senior Design Capstone course in the 2005- 2006 academic year. This educationally valuable software is being effectively used in an introductory Digital Logic Design (DLD) course. This paper presents the background and need for this type of software tool, a brief analysis of currently available tools and then explains its functionality and usefulness.

This easy to use logic simulator is valuable in both Digital Logic Design lectures and labs. The environment is graphical in nature and allows the user to very quickly build a logic circuit by clicking and dragging components from the reasonably complete library of gates and functions including: AND, OR, NOT, NAND, NOR, XOR, Multiplexers, Decoders, Adders, Comparators, Flip-Flops, Counters, Registers, RAM, ROM, and numerous Input and Output options. One of the most helpful features of this software is the simultaneous build and simulate environment with wires colored according to their logic value (Red for logic High and Black for logic Low). This allows the user to quickly understand how the logic is working and, if it is not working properly, to correct mistakes. The freshman students using this program for the first time have found it to be stable, helpful and in some cases even "fun" to play with and design.

The paper concludes with some lessons learned through the Senior Design Capstone experience from which this multi-threaded software was designed, written, debugged, revised and released for experimentation in DLD. CedarLogic's 10,000+ lines of code is written in C++ and utilizes the wxWidgets GUI library and OpenGL to render the graphics. CedarLogic can be freely downloaded at